unit Search;
interface
uses WinProcs, SysUtils, StdCtrls, Dialogs;
const
WordDelimiters: set of Char = [#0..#255] - ['a'..'z','A'..'Z','1'..'9','0'];
function SearchMemo(Memo: TCustomEdit;
const SearchString: String;Options: TFindOptions): Boolean;
function SearchBuf(Buf: PChar; BufLen: Integer;SelStart, SelLength: Integer;
SearchString: String;Options: TFindOptions): PChar;
implementation
function SearchMemo(Memo: TCustomEdit;const SearchString: String;
Options: TFindOptions): Boolean;
var
Buffer, P: PChar;
Size: Word;
begin
Result := False;
if (Length(SearchString) = 0) then Exit;
Size := Memo.GetTextLen;
if (Size = 0) then Exit;
Buffer := StrAlloc(Size + 1);
try
Memo.GetTextBuf(Buffer, Size + 1);
P := SearchBuf(Buffer, Size, Memo.SelStart,Memo.SelLength,SearchString, Options);
if P <> nil then
begin
Memo.SelStart := P - Buffer;
Memo.SelLength := Length(SearchString);
Result := True;
end;
finally
StrDispose(Buffer);
end;
end;
function SearchBuf(Buf: PChar; BufLen: Integer;SelStart, SelLength: Integer;
SearchString: String;Options: TFindOptions): PChar;
var
SearchCount, I: Integer;
C: Char;
Direction: Shortint;
CharMap: array [Char] of Char;
function FindNextWordStart(var BufPtr: PChar): Boolean;
begin { (True XOR N) is equivalent to (not N) }
// Result := False; { (False XOR N) is equivalent to (N) }
{ When Direction is forward (1), skip nondelimiters, then skip delimiters. }
{ When Direction is backward (-1), skip delims, then skip non delims }
while (SearchCount > 0) and ((Direction = 1) xor (BufPtr^ in WordDelimiters)) do
begin
Inc(BufPtr, Direction);
Dec(SearchCount);
end;
while (SearchCount > 0) and ((Direction = -1) xor (BufPtr^ in WordDelimiters)) do
begin
Inc(BufPtr, Direction);
Dec(SearchCount);
end;
Result := SearchCount > 0;
if Direction = -1 then
begin { back up one char, to leave ptr on first nondelim }
Dec(BufPtr, Direction);
Inc(SearchCount);
end;
end;
begin
Result := nil;
if BufLen <= 0 then Exit;
if frDown in Options then
begin
Direction := 1;
Inc(SelStart, SelLength); { start search past end of selection }
SearchCount := BufLen - SelStart - Length(SearchString);
if SearchCount < 0 then Exit;
if Longint(SelStart) + SearchCount > BufLen then
Exit;
end else
begin
Direction := -1;
Dec(SelStart, Length(SearchString));
SearchCount := SelStart;
end;
if (SelStart < 0) or (SelStart > BufLen) then Exit;
Result := @Buf[SelStart];
{ Using a Char map array is faster than calling AnsiUpper on every character }
for C := Low(CharMap) to High(CharMap) do
CharMap[C] := C;
if not (frMatchCase in Options) then
begin
AnsiUpperBuff(PChar(@CharMap), sizeof(CharMap));
AnsiUpperBuff(@SearchString[1],Length(SearchString));
end;
while SearchCount > 0 do
begin
if frWholeWord in Options then
if not FindNextWordStart(Result) then Break;
I := 0;
while (CharMap[Result] = SearchString[I+1]) do
begin
Inc(I);
if I >= Length(SearchString) then
begin
if (not (frWholeWord in Options)) or (SearchCount = 0) or
(Result in WordDelimiters) then
Exit;
Break;
end;
end;
Inc(Result, Direction);
Dec(SearchCount);
end;
Result := nil;
end;
end.
